The amount of information that can be concurrently maintained in the focus of attention is strongly restricted (Broadbent, 1958). The goal of this study was to test whether this restriction was functionally significant for language comprehension. We examined the time course dynamics of processing determiner-head agreement in English demonstrative phrases. We found evidence that agreement processing was slowed when determiner and head were no longer adjacent, but separated by modifiers. We argue that some information is shunted nearly immediately from the focus of attention, necessitating its later retrieval. Plural, the marked feature value for number, exhibits better preservation in the focus of attention, however, than the unmarked value, singular.

Language comprehension involves coping with ambiguity and recovering from misanalysis. Syntactic ambiguity resolution is associated with increased reading times, a classic finding that has shaped theories of sentence processing. However, reaction times conflate the time it takes a process to complete with the quality of the behavior-related information available to the system. We therefore used the speed-accuracy tradeoff procedure (SAT) to derive orthogonal estimates of processing time and interpretation accuracy, and tested whether stronger retrieval cues (via semantic relatedness: neighed->horse vs. fell->horse) aid interpretation during recovery. On average, ambiguous sentences took 250ms longer (SAT rate) to interpret than unambiguous controls, demonstrating veridical differences in processing time. Retrieval cues more strongly related to the true subject always increased accuracy, regardless of ambiguity. These findings are consistent with a language processing architecture where cue-driven operations give rise to interpretation, and wherein diagnostic cues aid retrieval, regardless of parsing difficulty or structural uncertainty.

In a Speed-Accuracy-Tradeoff (SAT) paradigm we investigated how adjective type and polarity modulate the online semantic composition of noun phrases (NPs). 22 German speakers read sentences like “The tradesman — buys — a real diamond”. Enriched adjectives (“real/fake”) highlighted or adjusted the noun’s meaning, whereas non-enriched adjectives (“white/flawed”) simply specified a property. Adjectives had positive (“white/real”) or negative polarity (“flawed/fake”). Upon the display of critical NPs, participants indicated by a series of key presses if the sentence was correct. For the SAT response function we computed the (i) asymptote (response accuracy as d’), (ii) rate (response speed) and (iii) intercept (point when accuracy departs from chance). Accuracy was significantly lower for semantically enriched vs. non-enriched NPs, suggesting that highlighting and adjusting certain properties during composition is costly. Polarity affected temporal dynamics with negative NPs showing a slower rate than positive NPs, indicating that negative information is processed in more depth.

One of the most replicated findings in neurolinguistic literature on syntax is the increase of hemodynamic activity in the left inferior frontal gyrus (LIFG) in response to object relative (OR) clauses compared to subject relative clauses. However, behavioral studies have shown that ORs are primarily only costly when similarity-based interference is involved and recently, Leiken and Pylkkänen (2014) showed with magnetoencephalography (MEG) that an LIFG increase at an OR gap is also dependent on such interference. However, since ORs always involve a cue indicating an upcoming dependency formation, OR dependencies could be processed already prior to the gap-site and thus show no sheer dependency effects at the gap itself. To investigate the role of gap predictability in LIFG dependency effects, this MEG study compared ORs to verb phrase ellipsis (VPE), which was used as an example of a non-predictable dependency. Additionally, we explored LIFG sensitivity to filler-gap order by including right node raising structures, in which the order of filler and gap is reverse to that of ORs and VPE. Half of the stimuli invoked similarity-based interference and half did not. Our results demonstrate that LIFG effects of dependency can be elicited regardless of whether the dependency is predictable, the stimulus materials evoke similarity-based interference, or the filler precedes the gap. Thus, contrary to our own prior data, the current findings suggest a highly general role for the LIFG in dependency interpretation that is not limited to environments involving similarity-based interference. Additionally, the millisecond time-resolution of MEG allowed for a detailed characterization of the temporal profiles of LIFG dependency effects across our three constructions, revealing that the timing of these effects is somewhat construction-specific.

When readers need to go beyond the straightforward compositional meaning of a sentence (i.e., when enriched composition is required), costly additional processing is the norm. However, this conclusion is based entirely on research that has looked at enriched composition between two phrases or within the verb phrase (e.g., the verb and its complement in . . . started the book . . . ) where there is a discrepancy between the semantic expectations of the verb and the semantics of the noun. We carried out an eye-tracking experiment investigating enriched composition within a single noun phrase, as in the difficult mountain. As compared with adjective–noun phrases that allow a straightforward compositional interpretation ( the difficult exercise ), the coerced phrases were more difficult to process. These results indicate that coercion effects can be found in the absence of a typing violation and within a single noun phrase.

Language comprehension requires recovering meaning from linguistic form, even when the mapping between the two is indirect. A canonical example is ellipsis, the omission of information that is subsequently understood without being overtly pronounced. Comprehension of ellipsis requires retrieval of an antecedent from memory, without prior prediction, a property which enables the study of retrieval in situ (Martin & McElree, 2008, 2009). Sluicing, or inflectional phrase ellipsis, in the presence of a conjunction, presents a test case where a competing antecedent position is syntactically licensed, in contrast with most cases of nonadjacent dependency, including verb phrase ellipsis. We present speed-accuracy tradeoff and eye-movement data inconsistent with the hypothesis that retrieval is accomplished via a syntactically guided search, a particular variant of search not examined in past research. The observed timecourse profiles are consistent with the hypothesis that antecedents are retrieved via a cue-dependent direct-access mechanism susceptible to general memory variables.

Comprehenders can rapidly and efficiently interpret expressions with various types of non-adjacent dependencies. In the sentence The boy that the teacher warned fell, boy is readily interpreted as the subject of the verb fall despite the fact that a relative clause, that the teacher warned, intervenes between the two dependent elements. We review research investigating three memory operations proposed for resolving this and other types of non-adjacent dependencies: serial search retrieval, in which the dependent constituent is recovered by a search process through representations in memory, direct-access retrieval in which the dependent constituent is recovered directly by retrieval cue operations without search, and active maintenance of the dependent constituent in focal attention. Studies using speed-accuracy tradeoff methodology to examine the full timecourse of interpreting a wide range of non-adjacent dependencies indicate that comprehenders retrieve dependent constituents with a direct-access operation, consistent with the claim that representations formed during comprehension are accessed with a cue-driven, content-addressable retrieval process. The observed timecourse profiles are inconsistent with a broad class of models based on several search operations for retrieval. The profiles are also inconsistent with active maintenance of a constituent while concurrently processing subsequent material, and suggest that, with few exceptions, direct-access retrieval is required to process non-adjacent dependencies.

Background: 1) In addition to improving discriminability, covert attention accelerates the rate of visual information processing (Carrasco & McElree, 2001). 2) Contrast sensitivity is better along the horizontal than vertical meridian and better at the South than North location. These asymmetries are more pronounced as eccentricity increases. Covert attention improves discriminability at all locations to a similar degree (Carrasco et al., 2001, 2002). 3) Recently we have found that information accrual is faster: (a) at far than near eccentricities, (b) at the horizontal than vertical meridian, and within the vertical meridian at the S than N location. Goal: We investigated whether covert attention affects the rate of visual information processing as a function of: (a) eccentricity (4 or 9 ), (b) location at a given eccentricity (cardinal and intercardinal points at 4 or 9 ). Methods: We collected time-course functions for orientation discrimination with the response-signal speed-accuracy trade-off (SAT) procedure. Each trial began with a cue (67 ms), which was either informative (dot indicating the target location) or neutral (a dot at fixation). After a 53 ms ISI, Gabor patches with 0 or 7 distracters appeared for 40 ms. The target and distracters were presented at 8 equidistant locations from fixation at 4 or 9 eccentricity. A tone sounded at 1 of 7 SOAs, ranging from 40 to 2000 ms, prompting observers to respond. Results: Covert attention accelerated information accrual: (a) similarly for far and near eccentricities, (b) more on the vertical than the horizontal meridian and more at the N than S location. Conclusion: Covert attention improves visual temporal dynamics to the same degree at different eccentricities, but it speeds up information accrual more at the least privileged locations, i.e. along the vertical meridian, thus eliminating temporal asymmetries at a given eccentricity.

Background: Covert attention increases discriminability and accelerates the rate of visual information processing (Carrasco & McElree, 2001). In addition, covert attention eliminates the temporal processing asymmetries that exist along the meridians of the visual field (i.e., temporal performance fields: information accrues faster in the horizontal than vertical meridian and in the North than South locations; Carrasco et al., 2004). Here we examined whether the effect of attention on information accrual varies with eccentricity (4° vs. 9°) and with search type (feature vs. conjunction). Methods: We collected time-course functions for orientation discrimination with the response-signal speed-accuracy trade-off (SAT) procedure. Each trial began with a cue (67 ms), peripheral (a circle adjacent to target location) or neutral (a circle at fixation). After a 53 ms ISI, a 2-cpd target Gabor patch (tilted either to the right or left) and 0 or 7 distracters appeared for 40 ms at 8 equidistant locations from fixation at 4° or 9° eccentricity. In the feature task, all distracters were vertical 2-cpd gratings. In the conjunction task, some distracters shared the orientation of the target and others shared its spatial frequency: the 2-cpd distracters were vertical patches; half the 8-cpd distracters were tilted to the left, and half to the right. To measure discriminability and information accrual conjointly from chance to asymptote, a tone sounded at 1 of 7 SOAs, ranging from 40 to 2000 ms, prompting observers to respond. Results: For all observers, information processing was faster at 9° than 4°, consistent with our previous findings. Covert attention increased discriminability and accelerated information accrual similarly for near and far eccentricities and for both feature and conjunction searches. In contrast to the compensatory effect of covert attention on temporal performance fields, covert attention did not eliminate speed differences across eccentricity.

The response-signal speed-accuracy trade-off (SAT) procedure was used to investigate the relationship between measures of working memory capacity and the time course of short-term item recognition. High- and low-span participants studied sequentially presented 6-item lists, immediately followed by a recognition probe. Analyses of composite list and serial position SAT functions found no differences in retrieval speed between the 2 span groups. Overall accuracy was higher for high spans than low spans, with more pronounced differences for earlier serial positions. Analysis of false alarms to recent negatives (lures from the previous study list) revealed no differences in the timing or magnitude of early false alarms, thought to reflect familiarity-based judgments. However, analyses of false alarms later in retrieval indicated that recollective information accrues more slowly for low spans, which suggests that recollective information may also contribute less to judgments concerning studied items for low-span participants. These findings can provide an explanation for the greater susceptibility of low spans to interference.

Neural activation in a 12-item probe-recognition task was examined to investigate the contribution of the hippocampus to long-term memory (LTM) retrieval and working memory (WM) retrieval. Results indicated a dissociation between the last item that participants studied and other items of the study list: Compared with all other serial positions, activation was reduced for the item in the most recent position (for which no items intervened between study and test). This finding suggests that this last item was in focal attention at test time, and, therefore, no retrieval operation was required to access it. However, contra the assertion that the hippocampus should selectively support LTM, activation of the medial temporal lobe was observed for all serial positions other than the last position, and activation level could be predicted from the underlying memory strength. Collectively, these findings support single-store accounts that assume there are similar operating principles across WM and LTM representations, and the focus of attention is limited.

Background: 1) Transient covert attention improves discriminability and accelerates the rate of visual information processing in feature and conjunction searches (Carrasco & McElree, 2001). 2) Contrast sensitivity and spatial resolution are better along the horizontal than vertical meridian, and covert attention improves discriminability at all locations to a similar degree (Carrasco et al., 2001; Talgar & Carrasco, In Press). Goal: We investigated whether: a) the rate of information processing differs for different locations at a fixed eccentricity; b) the effect of transient covert attention on the dynamics varies as a function of location. Methods: We used time-course functions derived from the response-signal speed-accuracy trade-off (SAT) procedure for an orientation feature discrimination task. Each trial began with a precue (67 ms), which was either informative (small circle, indicating the target location) or neutral (a circle in the middle of the display). After a 53 ms ISI, Gabor patches, with 0 or 7 distracters, appeared for 40 ms. The target and distracters were presented at 8 equidistant locations from fixation at 4° eccentricity. A tone sounded at 1 of 7 SOAs, ranging from 40 to 2000 ms, to prompt observers to respond. Results: a) SAT asymptotic accuracy (d′) was higher and the rate of information processing was faster at the locations on the horizontal than the vertical meridian; b) precueing the target location improved discriminability to a similar extent across the visual field but accelerated information accrual more on the vertical than the horizontal meridian. Conclusion: These results indicate that performance is superior on the horizontal than the vertical meridian because discriminability is higher and temporal dynamics are faster. Interestingly, whereas covert attention affects discriminability to a similar extent across the visual field, it speeds up information accrual more at the least privileged locations, i.e. on the vertical meridian.

Functional magnetic resonance imaging was used to identify regions involved in working memory (WM) retrieval. Neural activation was examined in two WM tasks: an item recognition task, which can be mediated by a direct-access retrieval process, and a judgment of recency task that requires a serial search. Dissociations were found in the activation patterns in the hippocampus and in the left inferior frontal gyrus (LIFG) when the probe contained the most recently studied serial position (where a test probe can be matched to the contents of focal attention) compared to when it contained all other positions (where retrieval is required). The data implicate the hippocampus and the LIFG in retrieval from WM, complementing their established role in long-term memory. Results further suggest that the left posterior parietal cortex (LPPC) supports serial retrieval processes that are often required to recover temporal order information. Together, these data suggest that the LPPC, the LIFG, and the hippocampus collectively support WM retrieval. Critically, the reported findings support accounts that posit a distinction between representations maintained in and outside of focal attention, but are at odds with traditional dual-store models that assume distinct mechanisms for short- and long-term memory representations.

Comprehension of verb-phrase ellipsis (VPE) requires reevaluation of recently processed constituents, which often necessitates retrieval of information about the elided constituent from memory. A. E. Martin and B. McElree (2008) argued that representations formed during comprehension are content addressable and that VPE antecedents are retrieved from memory via a cue-dependent direct-access pointer rather than via a search process.This hypothesis was further tested by manipulating the location of interfering material-either before the onset of the antecedent (proactive interference; PI) or intervening between antecedent and ellipsis site (retroactive interference; RI).The speed-accuracy tradeoff procedure was used to measure the time course of VPE processing.The location of the interfering material affected VPE comprehension accuracy: RI conditions engendered lower accuracy than PI conditions.Crucially, location did not affect the speed of processing VPE, which is inconsistent with both forward and backward search mechanisms.The observed time-course profiles are consistent with the hypothesis that VPE antecedents are retrieved via a cue-dependent direct-access operation.